The Electrospray MS equipment requested is required to enlarge the capabilities of a wellestablished and widely used mass spectrometric facility at Children's Hospital Oakland Research Institute (CHORI). The instrument will supplement an electron impact gas chromatograph-mass spectrometer (HP 5970) and a VG 30-250 quadrupole instrument primarily used in Fast Atom Bombardment and HPLC/MS modes. The recent commercialization of electrospray MS with its ability to analyze charged molecules from mass 100 - 1OOK Da has particularly excited protein chemists so colleagues at Children's Hospital Oakland and associates are demanding availability of this technique in addition to the other mass spectromethc techniques on offer by the facility. Purchase of the requested instrument will allow us to conduct (a) analysis of intact biopolymers (mainly proteins) of mass to 100,000 Da and (b) tandem mass spectrometry of smaller molecules (peptides, carbohydrates, complex lipids, polynucleosides). For this reason a highquality HPLC apparatus with pulse-free operation at 5-50mul/minute is also requested. A combined HPLC/electrospray tandem mass spectrometer should be capable of simultaneous separation, characterization and sequencing of tryptic peptides. The instrument can be interfaced with normal and microbore LC columns and with capillary zone electrophoresis to allow on-line separation and MS measurement. The primary users of this instrument will be (a) NIH funded investigators at Children's Hospital Oakland Research Institute (CHORI), (b) local investigators (mainly NIH funded) at U.C. Berkeley, the Lawrence Berkeley Laboratory, U. C. Davis and Letterman Army Hospital, San Francisco and (c) NIH funded investigators from across the nation. The major research component will involve protein and peptide analysis although the technique will be used in our other fields of interest (steroid conjugates, complex sugars and complex lipids). While we have identified one user group, the use of our facility and the instrument by other NIH supported researchers (primarily at CHORI and U.C. Berkeley) will be actively encouraged. When time allows, we will establish collaboration with other non-profit researchers. This type of equipment is not currently available anywhere in the San Francisco Bay area outside the facilities of one of the major instrument manufacturers (Finnigan Corp.). Thus we anticipate becoming an important local resource.